Is sda affect achievable with 4 identical speakers?
JonathanPeterson
Posts: 103
What if you have 4 identical speakers
You put two of them next to each other on the left. And out seconds pair to the right.
Inner most pair will get a regular stereo signal(speakers A on receiver)
Outermost pair(speakers B on receiver) will get 180 degree out of phase signal (just switch positive and negative terminals)
Will this be essentially the sda effect on early sda speakers with 2 tweeters next to each other horizontaly?
You put two of them next to each other on the left. And out seconds pair to the right.
Inner most pair will get a regular stereo signal(speakers A on receiver)
Outermost pair(speakers B on receiver) will get 180 degree out of phase signal (just switch positive and negative terminals)
Will this be essentially the sda effect on early sda speakers with 2 tweeters next to each other horizontaly?
Comments
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- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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The best approach would be to set up an amplified SDA arrangement. You would connect a speaker wire to the left and right positive terminals on your main amplifier or receiver. This is the "difference signal" between the two channels. This would be connected to a simple 10:1 voltage divider (a 1k resistor in series with a 10k resistor). This would reduce the difference signal to a line level signal, this would be fed to an aux input on an integrated amp or receiver. A pair of smaller speakers would be connected to the amp/receiver in opposite polarity to the main speakers. The treble would be reduced on the amp/receiver and the two speakers would reproduce the difference information and the level could be adjusted and placed to the sides of the main speakers.
This would be an active SDA system, similar to what was done in the SRT system.
Ken s- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit. -
Yes, it is possible to set up an SDA array with four identical speakers, but it is not easy to do it right.
Around 2008, Matthew Polk set up such a system in his home using four LSi9 speakers and a Rane digital signal processor. He and an assistant worked for some months on customizing and optimizing the Rane's software to accurately process the dimensional array signals.
The picture below is the right side LSi9-SDA array and the Rane DSP underneath.
Post edited by DarqueKnight onProud and loyal citizen of the Digital Domain and Solid State Country! -
Hats off to that undertaking. After seeing all the wires, I'm thankful for the simplified CRS+ crossovers.Don't take experimental gene therapies from known eugenicists.
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That's what I'm talkin' about!
I'm likin' that zip cord on the left! Is that Monster Cable?
In other SDA news: recent chatter on this forum leads me to recast a famed meme, out of deference to the older hands here.
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I have a friend, @OldmanSRS here on the forum, who has a pair of monitor 10s as his front speakers in his garage setup that have 2 small speakers beside the 10s that he uses to get SDA and it works really well. It is not as simple as the OP suggests by simply reversing polarity on the second set of speakers. Maybe he will chime in and describe what it did to make them work and sound so good.
- SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat
- Crossover upgrades by westmassguy
- Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
- Adcom GFA-555 amp · Upgrades & speaker protection added by OldmanSRS
- Pioneer DV-610AV DVD/CD player
- SDA CRS+ · Hidden away in the closet
- SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat
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DarqueKnight wrote: »Yes, it is possible to set up an SDA array with four identical speakers, but it is not easy to do it right.
Around 2008, Matthew Polk set up such a system in his home using four LSi9 speakers and a Rane digital signal processor. He and an assistant worked for some months on customizing and optimizing the Rane's software to accurately process the dimensional array signals.
The picture below is the right side LSi9-SDA array and the Rane DSP underneath.
I wonder how much of what Matt did back then has evolved into the current L800.
The Gear... Carver "Statement" Mono-blocks, Mcintosh C2800 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon 680d DSD
“When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson
How many flies need to be buzzing a dead horse before you guys stop beating it? -
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Yes I'm sure he would be willing to drop everything and have a lengthy conversation with the illustrious Jonathan Peterson.
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JonathanPeterson wrote: »Yes where is Mathew Polk. Is he available for an interview. Lots of people have questions. I heard he is in textile manufacturing business or something.
Since you stated you are not currently on medication it's time to start.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
Considering the rig pictured was for his house and that he sold the company I'd have to say zero.nooshinjohn wrote: »I wonder how much of what Matt did back then has evolved into the current L800.
Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
I have a friend, @OldmanSRS here on the forum, who has a pair of monitor 10s as his front speakers in his garage setup that have 2 small speakers beside the 10s that he uses to get SDA and it works really well. It is not as simple as the OP suggests by simply reversing polarity on the second set of speakers. Maybe he will chime in and describe what it did to make them work and sound so good.
TennMan, My thought process was; I'm using a pair of CRS+ speakers as the rear speakers in a multi- speaker 2-channel setup so why reinvent the wheel? I have SDA available so I just need to tap into it.
My solution to providing a SDA to the front pair Monitor 10's was to remove the SDA drivers(s) from the rear pair of CRS+ speakers and connect a 10:1 voltage divider using a 5K ohm to 0.5K resistor on each L/R CRS SDA driver. Using a pair of 20 gauge wires, I ran them from the voltage divider out of the speaker mounting hole when I re-installed the SDA drivers. (You can't see the wires with the grills on.) This provided an impedance matched, line level L/R output version of the CRS's L/R SDA signal. I fed this to a stereo integrated amp with line level and tone controls. I placed a Polk T-15 speaker on the outside edge of each Monitor 10 and wired them to the integrated amp driven by the CRS+ SDA signal.
I adjusted the "new front SDA" volume level until the new front Monitor 10 SDA effect sounded pleasant and matched. I also reduced the treble significantly because it added nothing to the spacial cues and was frankly, annoying. The SDA drivers can't reproduce those high frequencies so it's not an issue for them on the CRS+. I found a small amount of new front SDA goes a long way on my setup. The effect I get is a blending of the front and rear SDA that meets 90 degrees to the side. Varying the new front SDA volume moves the blending effect front to back somewhat. The overall size of the sweet spot is extended and improved.
'65 427 Shelby Cobra
'72 Triumph TR-6
__________________
'88 Polk SDA SRS 1.2, with upgraded XO caps and Erse SDA inductors
'86 Polk SDA CRS+
'84 Polk Monitor 10A (Peerless tweeters)
'05 HSU VTF-3 Sub (Original OEM)
'20 HSU VTF-3 Sub (three more, 100% cloned)
'93 Carver TFM-35
'88 Carver M-1.0t
'88 Adcom GFT-555
'88 Adcom GFP-555
'88 Adcom GFA-555 (upgraded/restored)
'88 Adcom GFA-555 (a second one upgraded/restored)
'05 Onkyo DV-555 media
'89 Fosgate 360 Digital Space Matrix
'89 Fosgate 360 Digital Space Matrix, internal surround amp bridged to drive only a center channel
'91 Kenwood Basic M1D Amp
'89 Pioneer Laser Disc media
'89 Sony SuperBeta HiFi media
One PGA2310 based custom built remote volume control
Four Polk T-15's
Four Polk TSi-200's
Four Polk TSi-100's
Two Polk CS-10's -
Quad SDA?Don't take experimental gene therapies from known eugenicists.
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Quad SDA?
Sort of, but quad implies 4ch/4speakers and this is 2CH 4-SDA in a multi speaker setup. There are 17 total speakers (including two HSU VTF3 subs running in stereo) and I actually run 3CH stereo (full range 2CH plus a center channel added) including five center channel speakers distributed over several locations. All the non sub speakers are Polk's, volume matched for their locations, and 3 are used to create a bi-pole effect behind center stage at the front end of the garage. It's complicated and it works great. It's a really nice, big, full, encompassing sound with DEEP base capability and great dynamic range. The room environment is acoustically very dead so there's no virtually no echo. Pipe organ music sounds like your are listening in a medieval granite cathedral. The garage is under the house and measures 72' X 26'. Center stage is 1/4 of the way from the front of the room. The optimum listening position is 1/2 to 2/3 from the front. Quality sound, nearly equal volume (dropping off about 6db at the far ends of the room on purpose) and stereo separation is available everywhere.'65 427 Shelby Cobra
'72 Triumph TR-6
__________________
'88 Polk SDA SRS 1.2, with upgraded XO caps and Erse SDA inductors
'86 Polk SDA CRS+
'84 Polk Monitor 10A (Peerless tweeters)
'05 HSU VTF-3 Sub (Original OEM)
'20 HSU VTF-3 Sub (three more, 100% cloned)
'93 Carver TFM-35
'88 Carver M-1.0t
'88 Adcom GFT-555
'88 Adcom GFP-555
'88 Adcom GFA-555 (upgraded/restored)
'88 Adcom GFA-555 (a second one upgraded/restored)
'05 Onkyo DV-555 media
'89 Fosgate 360 Digital Space Matrix
'89 Fosgate 360 Digital Space Matrix, internal surround amp bridged to drive only a center channel
'91 Kenwood Basic M1D Amp
'89 Pioneer Laser Disc media
'89 Sony SuperBeta HiFi media
One PGA2310 based custom built remote volume control
Four Polk T-15's
Four Polk TSi-200's
Four Polk TSi-100's
Two Polk CS-10's
